U.S. patent application number 14/080717 was filed with the patent office on 2015-03-26 for extended wear electrocardiography patch.
The applicant listed for this patent is Bardy Diagnostics, Inc.. Invention is credited to Gust H. Bardy, Jon Mikalson Bishay, Jason Felix.
Application Number | 20150087948 14/080717 |
Document ID | / |
Family ID | 52691529 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150087948 |
Kind Code |
A1 |
Bishay; Jon Mikalson ; et
al. |
March 26, 2015 |
Extended Wear Electrocardiography Patch
Abstract
Physiological monitoring can be provided through a wearable
monitor that includes a flexible extended wear electrode patch and
a removable reusable monitor recorder. The wearable monitor sits
centrally on the patient's chest along the sternum, which
significantly improves the ability to sense cutaneously cardiac
electric signals, particularly those generated by the atrium. The
electrode patch is shaped to fit comfortably and conformal to the
contours of the chest approximately centered on the sternal
midline. To counter the dislodgment due to compressional and
torsional forces, non-irritating adhesive is provided on the
underside, or contact, surface of the electrode patch, but only on
the distal and proximal ends. To counter dislodgment due to tensile
and torsional forces, a strain relief is defined in the electrode
patch's flexible circuit using cutouts partially extending
transversely from each opposite side of the flexible circuit and
continuing longitudinally towards each other to define in
`S`-shaped pattern.
Inventors: |
Bishay; Jon Mikalson;
(Seattle, WA) ; Bardy; Gust H.; (Carnation,
WA) ; Felix; Jason; (Vashon Island, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bardy Diagnostics, Inc. |
Vashon |
WA |
US |
|
|
Family ID: |
52691529 |
Appl. No.: |
14/080717 |
Filed: |
November 14, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61882403 |
Sep 25, 2013 |
|
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Current U.S.
Class: |
600/382 ;
600/391 |
Current CPC
Class: |
A61B 5/01 20130101; A61B
5/6823 20130101; A61B 5/4809 20130101; A61B 2560/0271 20130101;
A61B 2560/0412 20130101; A61B 5/6801 20130101; A61B 5/0816
20130101; A61B 5/04017 20130101; G01N 27/307 20130101; A61B 5/04085
20130101; A61B 5/0006 20130101; A61B 5/0452 20130101; A61B 5/0022
20130101; A61B 5/1117 20130101; A61B 5/02055 20130101; A61B 5/04087
20130101; A61B 5/021 20130101; A61B 2505/07 20130101; A61B 2562/164
20130101; A61B 5/087 20130101; A61B 5/1118 20130101; A61B 5/14532
20130101; A61B 5/14542 20130101; A61B 2560/045 20130101; A61B
5/04325 20130101; A61B 5/091 20130101; A61B 2562/0219 20130101;
A61B 5/6833 20130101; A61B 5/7455 20130101; A61B 5/04525 20130101;
A61B 5/1116 20130101; A61B 5/14551 20130101 |
Class at
Publication: |
600/382 ;
600/391 |
International
Class: |
A61B 5/0408 20060101
A61B005/0408; A61B 5/00 20060101 A61B005/00 |
Claims
1. An extended wear electrocardiography patch, comprising: a
flexible backing formed of an elongated strip of stretchable
material with a narrow longitudinal midsection evenly tapering
inward from both ends, the elongated strip adherable only on a
contact surface defined on each of the ends, and operable to serve
as a crimp relief to facilitate compression of the narrow
longitudinal midsection in response to compressional and torsional
forces; a pair of electrocardiographic electrodes respectively
affixed to and conductively exposed on the contact surface of each
end of the elongated strip; a flexible circuit affixed on each end
to the elongated strip and comprising a pair of circuit traces each
originating within one of the ends of the elongated strip,
respectively; and electrically coupled to one of the
electrocardiographic electrodes, respectively; a
laterally-extendable strain relief defined in the flexible circuit
and operable to facilitate extension and rotation of the flexible
circuit in response to tensile and torsional forces; and a
non-conductive receptacle securely adhered on one end of the
elongated strip opposite the contact surface and operable to
removably receive an electrocardiography monitor, the
non-conductive receptacle comprising electrode terminals aligned to
electrically interface the pair of the circuit traces to the
electrocardiography monitor.
2. An electrocardiography patch according to claim 1, further
comprising: one of the electrocardiographic electrodes being
disposed for being adhered to a region overlying the Xiphoid
process on a patient's chest; and an other of the
electrocardiographic electrodes being disposed for being adhered to
the region near the manubrium on the patient's chest oriented
centrally (in the midline) along the sternum upwards from the one
electrocardiographic electrode.
3. An electrocardiography patch according to claim 1, further
comprising: an upper part of the elongated strip defined on one end
of the flexible backing and sized to be affixed to the bottom
surface of the non-conductive receptacle, the other of the
electrocardiographic electrodes being affixed to and conductively
exposed on the contact surface of the upper part; and a lower part
of the elongated strip defined on another end of the flexible
backing; the one of the electrocardiographic electrodes being
affixed to and conductively exposed on the contact surface of the
lower part, wherein the lower part of the elongated strip is
provided for being adhered to the region overlying the Xiphoid
process on a patient's chest with the narrow longitudinal
midsection oriented centrally (in the midline) along the sternum
and the upper part of the elongated strip oriented upwards towards
the manubrium.
4. An electrocardiography patch according to claim 1, further
comprising: a non-irritating adhesive dressing at least partially
coated on each end of the elongated strip on the contact
surface.
5. An electrocardiography patch according to claim 1, further
comprising: a pair of strain relief cutouts comprised in the strain
relief that each face towards the other strain relief cutout, each
strain relief cutout partially extending transversely from and
continuing longitudinally to a side of the flexible circuit
different than the other strain relief cutout, one of the pair of
the circuit traces following a path formed on the flexible circuit
between the pair of the strain relief cutouts.
6. An electrocardiography patch according to claim 5, wherein the
pair of the strain relief cutouts define an `S`-shaped pattern in
the flexible circuit when viewed from above.
7. An electrocardiography patch to claim 1, wherein the narrow
longitudinal midsection defines an hourglass-shaped pattern in the
flexible backing when viewed from above conformal to fit
comfortably within the intermammary cleft of a patient's pair of
breasts.
8. An electrocardiography patch according to claim 1, further
comprising: a battery compartment provided in the non-conductive
receptacle and comprising a pair of battery leads electrically
coupleable to a battery; and the non-conductive receptacle further
comprising power terminals aligned to electrically interface the
pair of battery leads to the electrocardiography monitor.
9. An electrocardiography patch according to claim 1, further
comprising: a moisture-resistant seal formed on the non-conductive
receptacle circumferentially about the electrode terminals and
adapted to substantially protect the electrocardiography monitor
against moisture intrusion.
10. An electrocardiography patch according to claim 1, further
comprising: a contoured surface comprised on the non-irritating
adhesive dressing on at least one end of the elongated strip.
11. An electrocardiography patch according to claim 1, further
comprising: a plurality of fasteners comprised on the
non-conductive receptacle and oriented to securely receive and to
hold captive the electrocardiography monitor into the
non-conductive receptacle.
12. An electrocardiography patch according to claim 1, further
comprising at least one of: rounded edges defined about a bottom
surface of the non-conductive receptacle; a gel well
circumferentially defined about at least one of the
electrocardiographic electrodes on the contact surface of the end
of the flexible dressing on which the at least one
electrocardiographic electrode is affixed; and placement and
removal tabs comprised as part of the flexible backing and
extending longitudinally beyond at least one end of the flexible
dressing.
13. An extended wear hourglass-shaped electrocardiography patch,
comprising: a flexible backing formed of an elongated strip of
stretchable material with a narrow longitudinal midsection evenly
tapering inward from both ends into an hourglass-shaped pattern
when viewed from above; a contact surface of the flexible backing
comprising a non-irritating adhesive dressing at least partially
coated on each end and lacking the non-irritating adhesive dressing
on the narrow longitudinal midsection; a pair of
electrocardiographic electrodes respectively affixed to and
conductively exposed on the contact surface of each end of the
flexible backing; a flexible circuit affixed to each end of the
flexible backing, comprising: a pair of circuit traces each
originating within one of the ends of the flexible backing,
respectively; each circuit trace electrically coupled to one of the
electrocardiographic electrodes, respectively; and a pair of strain
relief cutouts that each face towards the other strain relief
cutout, each strain relief cutout partially extending transversely
from and continuing longitudinally to a side of the flexible
circuit different than the other strain relief cutout, one of the
pair of the circuit traces following a path formed on the flexible
circuit between the pair of the strain relief cutouts; and a
non-conductive receptacle securely adhered on the one end of the
flexible backing opposite the contact surface and operable to
removably receive an electrocardiography monitor.
14. An electrocardiography patch according to claim 13, wherein one
of the electrocardiographic electrodes is disposed for being
adhered to a region overlying the Xiphoid process on a patient's
chest and the other of the electrocardiographic electrodes is
disposed for being adhered to the region in near the manubrium
upwards and oriented centrally (in the midline) along the sternum
upwards from the one electrocardiographic electrode.
15. An electrocardiography patch according to claim 13, further
comprising: an upper part of the hourglass-shaped pattern sized to
seat the non-conductive receptacle on an outward-facing surface of
the flexible backing; and a lower part of the hourglass-shaped
pattern comprising a size smaller than the upper part of the
hourglass-shaped pattern.
16. An electrocardiography patch according to claim 15, wherein the
lower part is provided for being adhered to the region overlying
the Xiphoid process on a patient's chest with the narrow
longitudinal midsection oriented centrally (in the midline) along
the sternum and the upper part oriented upwards towards the
manubrium.
17. An electrocardiography patch according to claim 13, further
comprising: the non-conductive receptacle comprising electrode
terminals aligned to electrically interface the
electrocardiographic electrodes via the pair of the circuit traces
to the electrocardiography monitor.
18. An electrocardiography patch according to claim 13, further
comprising: a pair of concave cut-outs defined along the
longitudinal edges of the elongated strip, each concave cut-out
contoured conformal to substantially clear an intermammary
cleft.
19. An electrocardiography patch according to claim 13, further
comprising: a battery comprised in the non-conductive receptacle
and disposed to provide power to the electrocardiography
monitor.
20. An electrocardiography patch according to claim 13, wherein the
stretchable material comprises at least one of wearable gauze,
wearable latex, wrap knit fabric, and Tricot linen.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This non-provisional patent application claims priority
under 35 U.S.C. .sctn.119(e) to U.S. Provisional Patent
application, Ser. No. 61/882,403, filed Sep. 25, 2013, the
disclosure of which is incorporated by reference.
FIELD
[0002] This application relates in general to electrocardiographic
monitoring and, in particular, to an extended wear
electrocardiography patch.
BACKGROUND
[0003] The heart emits electrical signals as a by-product of the
propagation of the action potentials that trigger depolarization of
heart fibers. An electrocardiogram (ECG) measures and records such
electrical potentials to visually depict the electrical activity of
the heart over time. Conventionally, a standardized set format
12-lead configuration is used by an ECG machine to record cardiac
electrical signals from well-established traditional chest
locations. Electrodes at the end of each lead are placed on the
skin over the anterior thoracic region of the patient's body to the
lower right and to the lower left of the sternum, on the left
anterior chest, and on the limbs. Sensed cardiac electrical
activity is represented by PQRSTU waveforms that can be interpreted
post-ECG recordation to derive heart rate and physiology. The
P-wave represents atrial electrical activity. The QRSTU components
represent ventricular electrical activity.
[0004] An ECG is a tool used by physicians to diagnose heart
problems and other potential health concerns. An ECG is a snapshot
of heart function, typically recorded over 12 seconds, that can
help diagnose rate and regularity of heartbeats, effect of drugs or
cardiac devices, including pacemakers and implantable
cardioverter-defibrillators (ICDs), and whether a patient has heart
disease. ECGs are used in-clinic during appointments, and, as a
result, are limited to recording only those heart-related aspects
present at the time of recording. Sporadic conditions that may not
show up during a spot ECG recording require other means to diagnose
them. These disorders include fainting or syncope; rhythm
disorders, such as tachyarrhythmias and bradyarrhythmias; apneic
episodes; and other cardiac and related disorders. Thus, an ECG
only provides a partial picture and can be insufficient for
complete patient diagnosis of many cardiac disorders.
[0005] Diagnostic efficacy can be improved, when appropriate,
through the use of long-term extended ECG monitoring. Recording
sufficient ECG and related physiology over an extended period is
challenging, and often essential to enabling a physician to
identify events of potential concern. A 30-day observation day
period is considered the "gold standard" of ECG monitoring, yet
achieving a 30-day observation day period has proven unworkable
because such ECG monitoring systems are arduous to employ,
cumbersome to the patient, and excessively costly. Ambulatory
monitoring in-clinic is implausible and impracticable.
Nevertheless, if a patient's ECG could be recorded in an ambulatory
setting, thereby allowing the patient to engage in activities of
daily living, the chances of acquiring meaningful information and
capturing an abnormal event while the patient is engaged in normal
activities becomes more likely to be achieved.
[0006] For instance, the long-term wear of ECG electrodes is
complicated by skin irritation and the inability ECG electrodes to
maintain continual skin contact after a day or two. Moreover, time,
dirt, moisture, and other environmental contaminants, as well as
perspiration, skin oil, and dead skin cells from the patient's
body, can get between an ECG electrode, the non-conductive adhesive
used to adhere the ECG electrode, and the skin's surface. All of
these factors adversely affect electrode adhesion and the quality
of cardiac signal recordings. Furthermore, the physical movements
of the patient and their clothing impart various compressional,
tensile, and torsional forces on the contact point of an ECG
electrode, especially over long recording times, and an inflexibly
fastened ECG electrode will be prone to becoming dislodged.
Moreover, dislodgment may occur unbeknownst to the patient, making
the ECG recordings worthless. Further, some patients may have skin
that is susceptible to itching or irritation, and the wearing of
ECG electrodes can aggravate such skin conditions. Thus, a patient
may want or need to periodically remove or replace ECG electrodes
during a long-term ECG monitoring period, whether to replace a
dislodged electrode, reestablish better adhesion, alleviate itching
or irritation, allow for cleansing of the skin, allow for showering
and exercise, or for other purpose. Such replacement or slight
alteration in electrode location actually facilitates the goal of
recording the ECG signal for long periods of time.
[0007] Conventionally, Holter monitors are widely used for
long-term extended ECG monitoring. Typically, they are often used
for only 24-48 hours. A typical Holter monitor is a wearable and
portable version of an ECG that include cables for each electrode
placed on the skin and a separate battery-powered ECG recorder. The
cable and electrode combination (or leads) are placed in the
anterior thoracic region in a manner similar to what is done with
an in-clinic standard ECG machine. The duration of a Holter
monitoring recording depends on the sensing and storage
capabilities of the monitor, as well as battery life. A "looping"
Holter (or event) monitor can operate for a longer period of time
by overwriting older ECG tracings, thence "recycling" storage in
favor of extended operation, yet at the risk of losing event data.
Although capable of extended ECG monitoring, Holter monitors are
cumbersome, expensive and typically only available by medical
prescription, which limits their usability. Further, the skill
required to properly place the electrodes on the patient's chest
hinders or precludes a patient from replacing or removing the
precordial leads and usually involves moving the patient from the
physician office to a specialized center within the hospital or
clinic.
[0008] The ZIO XT Patch and ZIO Event Card devices, manufactured by
iRhythm Tech., Inc., San Francisco, Calif., are wearable stick-on
monitoring devices that are typically worn on the upper left
pectoral region to respectively provide continuous and looping ECG
recording. The location is used to simulate surgically implanted
monitors. Both of these devices are prescription-only and for
single patient use. The ZIO XT Patch device is limited to a 14-day
monitoring period, while the electrodes only of the ZIO Event Card
device can be worn for up to 30 days. The ZIO XT Patch device
combines both electronic recordation components and physical
electrodes into a unitary assembly that adheres to the patient's
skin. The ZIO XT Patch device uses adhesive sufficiently strong to
support the weight of both the monitor and the electrodes over an
extended period of time and to resist disadherance from the
patient's body, albeit at the cost of disallowing removal or
relocation during the monitoring period. The ZIO Event Card device
is a form of downsized Holter monitor with a recorder component
that must be removed temporarily during baths or other activities
that could damage the non-waterproof electronics. Both devices
represent compromises between length of wear and quality of ECG
monitoring, especially with respect to ease of long term use,
female-friendly fit, and quality of atrial (P-wave) signals.
[0009] Therefore, a need remains for an extended wear continuously
recording ECG monitor practicably capable of being worn for a long
period of time, especially in women where breast anatomy can
interfere with signal quality in both men and women and capable of
recording atrial signals reliably.
[0010] A further need remains for a device capable of recording
signals ideal for arrhythmia discrimination, especially a device
designed for atrial activity recording.
SUMMARY
[0011] Physiological monitoring can be provided through a wearable
monitor that includes two components, a flexible extended wear
electrode patch and a removable reusable monitor recorder. The
wearable monitor sits centrally (in the midline) on the patient's
chest along the sternum oriented top-to-bottom. The placement of
the wearable monitor in a location at the sternal midline (or
immediately to either side of the sternum), with its unique narrow
"hourglass"-like shape, significantly improves the ability of the
wearable monitor to cutaneously sense cardiac electric signals,
particularly the P-wave (or atrial activity) and, to a lesser
extent, the QRS interval signals in the ECG waveforms indicating
ventricular activity. The electrode patch is shaped to fit
comfortably and conformal to the contours of the patient's chest
approximately centered on the sternal midline. To counter the
dislodgment due to compressional and torsional forces, a layer of
non-irritating adhesive, such as hydrocolloid, is provided at least
partially on the underside, or contact, surface of the electrode
patch, but only on the electrode patch's distal and proximal ends.
To counter dislodgment due to tensile and torsional forces, a
strain relief is defined in the electrode patch's flexible circuit
using cutouts partially extending transversely from each opposite
side of the flexible circuit and continuing longitudinally towards
each other to define in `S`-shaped pattern. Each of these
components are distinctive and allow for comfortable and extended
wear, especially by women, where breast mobility would otherwise
interfere with monitor use and comfort.
[0012] One embodiment provides an extended wear electrocardiography
patch. A flexible backing is formed of an elongated strip of
stretchable material with a narrow longitudinal midsection evenly
tapering inward from both ends. The elongated strip is adherable
only on each end of a contact surface to serve as a crimp relief to
facilitate compression of the narrow longitudinal midsection in
response to compressional and torsional forces. A pair of
electrocardiographic electrodes is respectively affixed to and
conductively exposed on the contact surface of each end of the
elongated strip. A flexible circuit is affixed on each end to the
elongated strip. The flexible circuit includes a pair of circuit
traces both originating within one of the ends of the elongated
strip and which are electrically coupled to each
electrocardiographic electrode. A laterally-extendable strain
relief is defined in the flexible circuit and formed to facilitate
extension and rotation of the flexible circuit in response to
tensile and torsional forces. A non-conductive receptacle is
securely adhered on the one end of the elongated strip opposite the
contact surface and is formed to removably receive an
electrocardiography monitor. The non-conductive receptacle includes
electrode terminals aligned to electrically interface the pair of
circuit traces to the electrocardiography monitor.
[0013] A further embodiment provides an extended wear
hourglass-shaped electrocardiography patch. A flexible backing is
formed of an elongated strip of stretchable material with a narrow
longitudinal midsection evenly tapering inward from both ends into
an hourglass-shaped pattern when viewed from above. A contact
surface of the flexible backing includes a non-irritating adhesive
dressing at least partially coated on each end and lacking the
non-irritating adhesive dressing on the narrow longitudinal
midsection. A pair of electrocardiographic electrodes is
respectively affixed to and conductively exposed on the contact
surface of each end of the flexible backing. A flexible circuit is
affixed to each end to the flexible backing. A pair of circuit
traces both originate within one of the ends of the flexible
backing Each circuit trace is electrically coupled to one of the
electrocardiographic electrodes. A pair of strain relief cutouts
each face towards the other strain relief cutout. Each strain
relief cutout partially extends transversely from and continuing
longitudinally to a side of the flexible circuit different than the
other strain relief cutout. One of the pair of circuit traces
follows a path formed on the flexible circuit between the pair of
strain relief cutouts. A non-conductive receptacle is securely
adhered on the one end of the flexible backing opposite the contact
surface and is formed to removably receive an electrocardiography
monitor.
[0014] The monitoring patch is especially suited to the female
anatomy. The narrow longitudinal midsection can fit nicely within
the intermammary cleft of the breasts without inducing discomfort,
whereas conventional patch electrodes are wide and, if adhesed
between the breasts, would cause chafing, irritation, frustration,
and annoyance, leading to low patient compliance.
[0015] The foregoing aspects enhance ECG monitoring performance and
quality facilitating long-term ECG recording, critical to accurate
arrhythmia diagnosis.
[0016] In addition, the foregoing aspects enhance comfort in women
(and certain men), but not irritation of the breasts, by placing
the monitoring patch in the best location possible for optimizing
the recording of cardiac signals from the atrium, another feature
critical to proper arrhythmia diagnosis.
[0017] Still other embodiments will become readily apparent to
those skilled in the art from the following detailed description,
wherein are described embodiments by way of illustrating the best
mode contemplated. As will be realized, other and different
embodiments are possible and the embodiments' several details are
capable of modifications in various obvious respects, all without
departing from their spirit and the scope. Accordingly, the
drawings and detailed description are to be regarded as
illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1 and 2 are diagrams showing, by way of examples, an
extended wear electrocardiography monitor, including an extended
wear electrode patch in accordance with one embodiment,
respectively fitted to the sternal region of a female patient and a
male patient.
[0019] FIG. 3 is a perspective view showing an extended wear
electrode patch in accordance with one embodiment with a monitor
recorder inserted.
[0020] FIG. 4 is a perspective view showing the extended wear
electrode patch of FIG. 3 without a monitor recorder inserted.
[0021] FIG. 5 is a top view showing the flexible circuit of the
extended wear electrode patch of FIG. 3.
[0022] FIG. 6 is a perspective view showing the extended wear
electrode patch in accordance with a further embodiment.
[0023] FIG. 7 is an exploded view showing the component layers of
the electrode patch of FIG. 3.
[0024] FIG. 8 is a bottom plan view of the extended wear electrode
patch of FIG. 3 with liner partially peeled back.
DETAILED DESCRIPTION
[0025] Physiological monitoring can be provided through a wearable
monitor that includes two components, a flexible extended wear
electrode patch and a removable reusable monitor recorder. FIGS. 1
and 2 are diagrams showing, by way of examples, an extended wear
electrocardiography monitor 12, including an extended wear
electrode patch 15 in accordance with one embodiment, respectively
fitted to the sternal region of a female patient 10 and a male
patient 11. The wearable monitor 12 sits centrally (in the midline)
on the patient's chest along the sternum 13 oriented top-to-bottom
with the monitor recorder 14 preferably situated towards the
patient's head. The electrode patch 15 is shaped to fit comfortably
and conformal to the contours of the patient's chest approximately
centered on the sternal midline 16 (or immediately to either side
of the sternum 13). The distal end of the electrode patch 15
extends towards the Xiphoid process and, depending upon the
patient's build, may straddle the region over the Xiphoid process.
The proximal end of the electrode patch 15, located under the
monitor recorder 14, is below the manubrium and, depending upon
patient's build, may straddle the region over the manubrium.
[0026] The placement of the wearable monitor 12 in a location at
the sternal midline 16 (or immediately to either side of the
sternum 13) significantly improves the ability of the wearable
monitor 12 to cutaneously sense cardiac electric signals,
particularly the P-wave (or atrial activity) and, to a lesser
extent, the QRS interval signals in the ECG waveforms that indicate
ventricular activity. The sternum 13 overlies the right atrium of
the heart and the placement of the wearable monitor 12 in the
region of the sternal midline 13 puts the ECG electrodes of the
electrode patch 15 in a location better adapted to sensing and
recording P-wave signals than other placement locations, say, the
upper left pectoral region. In addition, placing the lower or
inferior pole (ECG electrode) of the electrode patch 15 over (or
near) the Xiphoid process facilitates sensing of right ventricular
activity and provides superior recordation of the QRS interval.
[0027] During use, the electrode patch 15 is first adhesed to the
skin along the sternal midline 16 (or immediately to either side of
the sternum 13). A monitor recorder 14 is then snapped into place
on the electrode patch 15 to initiate ECG monitoring. FIG. 3 is a
perspective view showing an extended wear electrode patch 15 in
accordance with one embodiment with a monitor recorder 14 inserted.
The body of the electrode patch 15 is preferably constructed using
a flexible backing 20 formed as an elongated strip 21 of wrap knit
or similar stretchable material about 145 mm long and 32 mm at the
widest point with a narrow longitudinal mid-section 23 evenly
tapering inward from both sides. A pair of cut-outs 22 between the
distal and proximal ends of the electrode patch 15 create a narrow
longitudinal midsection 23 or "isthmus" and defines an elongated
"hourglass"-like shape, when viewed from above, such as described
in commonly-assigned U.S. Design patent application, entitled
"Extended Wear Electrode Patch," Serial No. 29/472,045, filed Nov.
7, 2013, pending, the disclosure of which is incorporated by
reference. The upper part of the "hourglass" is sized to allow an
electrically non-conductive receptacle 25, sits on top of the
outward-facing surface of the electrode patch 15, to be affixed to
the electrode patch 15 with an ECG electrode placed underneath on
the patient-facing underside, or contact, surface of the electrode
patch 15; the upper part of the "hourglass" has a longer and wider
profile than the lower part of the "hourglass," which is sized
primarily to allow just the placement of an ECG electrode.
[0028] The electrode patch 15 incorporates features that
significantly improve wearability, performance, and patient comfort
throughout an extended monitoring period. During wear, the
electrode patch 15 is susceptible to pushing, pulling, and
torqueing movements, including compressional and torsional forces
when the patient bends forward, and tensile and torsional forces
when the patient leans backwards. To counter these stress forces,
the electrode patch 15 incorporates crimp and strain reliefs, as
further described infra respectively with reference to FIGS. 4 and
5. In addition, the cut-outs 22 and longitudinal midsection 23 help
minimize interference with and discomfort to breast tissue,
particularly in women (and gynecomastic men). The cut-outs 22 and
longitudinal midsection 23 allow better conformity of the electrode
patch 15 to sternal bowing and to the narrow isthmus of flat skin
that can occur along the bottom of the intermammary cleft between
the breasts, especially in buxom women. The cut-outs 22 and
longitudinal midsection 23 help the electrode patch 15 fit nicely
between a pair of female breasts in the intermammary cleft. In one
embodiment, the cut-outs 22 can be graduated to form the
longitudinal midsection 23 as a narrow in-between stem or isthmus
portion about 7 mm wide. In a still further embodiment, tabs 24 can
respectively extend an additional 8 mm to 12 mm beyond the distal
and proximal ends of the flexible backing 20 to facilitate purchase
when adhering the electrode patch 15 to or removing the electrode
patch 15 from the sternum 13. These tabs preferably lack adhesive
on the underside, or contact, surface of the electrode patch 15.
Still other shapes, cut-outs and conformities to the electrode
patch 15 are possible.
[0029] The monitor recorder 14 removably and reusably snaps into an
electrically non-conductive receptacle 25 during use. The monitor
recorder 14 contains electronic circuitry for recording and storing
the patient's electrocardiography as sensed via a pair of ECG
electrodes provided on the electrode patch 15, such as described in
commonly-assigned U.S. patent application, entitled "Extended Wear
Ambulatory Electrocardiography and Physiological Sensor Monitor,"
Ser. No. ______, filed ______, pending, the disclosure of which is
incorporated by reference. The circuitry includes a
microcontroller, flash storage, ECG signal processing,
analog-to-digital conversion (where applicable), and an external
interface for coupling to the electrode patch 15 and to an download
station for stored data download and device programming. The
monitor recorder 14 also includes external patient-interfaceable
controls, such as a push button to facilitate event marking and a
resonance circuit to provide vibratory output. In a further
embodiment, the circuitry, with the assistance of the appropriate
types of deployed electrodes or sensors, is capable of monitoring
other types of physiology, in addition to ECGs. Still other types
of monitor recorder components and functionality are possible.
[0030] The non-conductive receptacle 25 is provided on the top
surface of the flexible backing 20 with a retention catch 26 and
tension clip 27 molded into the non-conductive receptacle 25 to
conformably receive and securely hold the monitor recorder 14 in
place. The edges of the bottom surface of the non-conductive
receptacle 25 are preferably rounded, and the monitor recorder 14
is nestled inside the interior of the non-conductive receptacle 25
to present a rounded (gentle) surface, rather than a sharp edge at
the skin-to-device interface.
[0031] The electrode patch 15 is intended to be disposable. The
monitor recorder 14, however, is reusable and can be transferred to
successive electrode patches 15 to ensure continuity of monitoring.
The placement of the wearable monitor 12 in a location at the
sternal midline 16 (or immediately to either side of the sternum
13) benefits long-term extended wear by removing the requirement
that ECG electrodes be continually placed in the same spots on the
skin throughout the monitoring period. Instead, the patient is free
to place an electrode patch 15 anywhere within the general region
of the sternum 13.
[0032] As a result, at any point during ECG monitoring, the
patient's skin is able to recover from the wearing of an electrode
patch 15, which increases patient comfort and satisfaction, while
the monitor recorder 14 ensures ECG monitoring continuity with
minimal effort. A monitor recorder 14 is merely unsnapped from a
worn out electrode patch 15, the worn out electrode patch 15 is
removed from the skin, a new electrode patch 15 is adhered to the
skin, possibly in a new spot immediately adjacent to the earlier
location, and the same monitor recorder 14 is snapped into the new
electrode patch 15 to reinitiate and continue the ECG
monitoring.
[0033] During use, the electrode patch 15 is first adhered to the
skin in the sternal region. FIG. 4 is a perspective view showing
the extended wear electrode patch 15 of FIG. 3 without a monitor
recorder 14 inserted. A flexible circuit 32 is adhered to each end
of the flexible backing 20. A distal circuit trace 33 from the
distal end 30 of the flexible backing 20 and a proximal circuit
trace (not shown) from the proximal end 31 of the flexible backing
20 electrically couple ECG electrodes (not shown) to a pair of
electrical pads 34. The electrical pads 34 are provided within a
moisture-resistant seal 35 formed on the bottom surface of the
non-conductive receptacle 25. When the monitor recorder 14 is
securely received into the non-conductive receptacle 25, that is,
snapped into place, the electrical pads 34 interface to electrical
contacts (not shown) protruding from the bottom surface of the
monitor recorder 14, and the moisture-resistant seal 35 enables the
monitor recorder 14 to be worn at all times, even during bathing or
other activities that could expose the monitor recorder 14 to
moisture.
[0034] In addition, a battery compartment 36 is formed on the
bottom surface of the non-conductive receptacle 25, and a pair of
battery leads (not shown) electrically interface the battery to
another pair of the electrical pads 34. The battery contained
within the battery compartment 35 can be replaceable, rechargeable
or disposable.
[0035] The monitor recorder 14 draws power externally from the
battery provided in the non-conductive receptacle 25, thereby
uniquely obviating the need for the monitor recorder 14 to carry a
dedicated power source. The battery contained within the battery
compartment 35 can be replaceable, rechargeable or disposable. In a
further embodiment, the ECG sensing circuitry of the monitor
recorder 14 can be supplemented with additional sensors, including
an SpO.sub.2 sensor, a blood pressure sensor, a temperature sensor,
respiratory rate sensor, a glucose sensor, an air flow sensor, and
a volumetric pressure sensor, which can be incorporated directly
into the monitor recorder 14 or onto the non-conductive receptacle
25.
[0036] The placement of the flexible backing 20 on the sternal
midline 16 (or immediately to either side of the sternum 13) also
helps to minimize the side-to-side movement of the wearable monitor
12 in the left- and right-handed directions during wear. However,
the wearable monitor 12 is still susceptible to pushing, pulling,
and torqueing movements, including compressional and torsional
forces when the patient bends forward, and tensile and torsional
forces when the patient leans backwards. To counter the dislodgment
of the flexible backing 20 due to compressional and torsional
forces, a layer of non-irritating adhesive, such as hydrocolloid,
is provided at least partially on the underside, or contact,
surface of the flexible backing 20, but only on the distal end 30
and the proximal end 31. As a result, the underside, or contact
surface of the longitudinal midsection 23 does not have an adhesive
layer and remains free to move relative to the skin. Thus, the
longitudinal midsection 23 forms a crimp relief that respectively
facilitates compression and twisting of the flexible backing 20 in
response to compressional and torsional forces. Other forms of
flexible backing crimp reliefs are possible.
[0037] Unlike the flexible backing 20, the flexible circuit 32 is
only able to bend and cannot stretch in a planar direction. FIG. 5
is a top view showing the flexible circuit 32 of the extended wear
electrode patch 15 of FIG. 3. A distal ECG electrode 38 and
proximal ECG electrode 39 are respectively coupled to the distal
and proximal ends of the flexible circuit 32. The flexible circuit
32 preferably does not extend to the outside edges of the flexible
backing 20, thereby avoiding gouging or discomforting the patient's
skin during extended wear, such as when sleeping on the side.
During wear, the ECG electrodes 38, 39 must remain in continual
contact with the skin. A strain relief 40 is defined in the
flexible circuit 32 at a location that is partially underneath the
battery compartment 36 when the flexible circuit 32 is affixed to
the flexible backing 20. The strain relief 40 is laterally
extendable to counter dislodgment of the ECG electrodes 38, 39 due
to tensile and torsional forces. A pair of strain relief cutouts 41
partially extend transversely from each opposite side of the
flexible circuit 32 and continue longitudinally towards each other
to define in `S`-shaped pattern, when viewed from above. The strain
relief respectively facilitates longitudinal extension and twisting
of the flexible circuit 32 in response to tensile and torsional
forces. Other forms of circuit board strain relief are
possible.
[0038] The flexible circuit 32 can be provided either above or
below the flexible backing 20. FIG. 6 is a perspective view showing
the extended wear electrode patch 15 in accordance with a further
embodiment. The flexible circuit (not shown) is provided on the
underside, or contact, surface of the flexible backing 20 and is
electrically interfaced to the set of electrical pads 34 on the
bottom surface of the non-conductive receptacle 25 through
electrical contacts (not shown) pierced through the flexible
backing 20.
[0039] The electrode patch 15 is intended to be a disposable
component, which enables a patient to replace the electrode patch
15 as needed throughout the monitoring period, while maintaining
continuity of physiological sensing through reuse of the same
monitor recorder 14. FIG. 7 is an exploded view showing the
component layers of the electrode patch 15 of FIG. 3. The flexible
backing 20 is constructed of a wearable gauze, latex, or similar
wrap knit or stretchable and wear-safe material 44, such as a
Tricot-type linen with a pressure sensitive adhesive (PSA) on the
underside, or contact, surface. The wearable material 44 is coated
with a layer 43 of non-irritating adhesive, such as hydrocolloid,
to facilitate long-term wear. The hydrocolloid, for instance, is
typically made of mineral oil, cellulose and water and lacks any
chemical solvents, so should cause little itching or irritation.
Moreover, hydrocolloid is thicker and more gel-like than most forms
of PSA and provides cushioning between the relatively rigid and
unyielding non-conductive receptacle 25 and the patient's skin. In
a further embodiment, the layer of non-irritating adhesive can be
contoured, such as by forming the adhesive with a concave or convex
cross-section; surfaced, such as through stripes or crosshatches of
adhesive, or by forming dimples in the adhesive's surface; or
applied discontinuously, such as with a formation of discrete dots
of adhesive.
[0040] As described supra with reference to FIG. 5, a flexible
circuit can be adhered to either the outward facing surface or the
underside, or contact, surface of the flexible backing 20. For
convenience, a flexible circuit 47 is shown relative to the outward
facing surface of the wearable material 44 and is adhered
respectively on a distal end by a distal electrode seal 45 and on a
proximal end by a proximal electrode seal 45. In a further
embodiment, the flexible circuit 47 can be provided on the
underside, or contact, surface of the wearable material 44. Through
the electrode seals, only the distal and proximal ends of the
flexible circuit 47 are attached to the wearable material 44, which
enables the strain relief 40 (shown in FIG. 5) to respectively
longitudinally extend and twist in response to tensile and
torsional forces during wear. Similarly, the layer 43 of
non-irritating adhesive is provided on the underside, or contact,
surface of the wearable material 44 only on the proximal and distal
ends, which enables the longitudinal midsection 23 (shown in FIG.
3) to respectively bow outward and away from the sternum 13 or
twist in response to compressional and torsional forces during
wear.
[0041] A pair of openings 46 is defined on the distal and proximal
ends of the wearable material 44 and layer 43 of non-irritating
adhesive for ECG electrodes 38, 39 (shown in FIG. 5). The openings
46 serve as "gel" wells with a layer of hydrogel 41 being used to
fill the bottom of each opening 46 as a conductive material that
aids electrode signal pick up. The entire underside, or contact,
surface of the flexible backing 20 is protected prior to use by a
liner layer 40 that is peeled away, as shown in FIG. 8.
[0042] The non-conductive receptacle 25 includes a main body 54
that is molded out of polycarbonate, ABS, or an alloy of those two
materials to provide a high surface energy to facilitate adhesion
of an adhesive seal 53. The main body 54 is attached to a battery
printed circuit board 52 by the adhesive seal 53 and, in turn, the
battery printed circuit board 52 is adhesed to the flexible circuit
47 with an upper flexible circuit seal 50. A pair of conductive
transfer adhesive points 51 or, alternatively, metallic rivets or
similar conductive and structurally unifying components, connect
the circuit traces 33, 37 (shown in FIG. 5) of the flexible circuit
47 to the battery printed circuit board 52. The main body 54 has a
retention catch 26 and tension clip 27 (shown in FIG. 3) that
fixably and securely receive a monitor recorder 14 (not shown), and
includes a recess within which to circumferentially receive a die
cut gasket 55, either rubber, urethane foam, or similar suitable
material, to provide a moisture resistant seal to the set of pads
34.
[0043] While the invention has been particularly shown and
described as referenced to the embodiments thereof, those skilled
in the art will understand that the foregoing and other changes in
form and detail may be made therein without departing from the
spirit and scope.
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